Laserfiche WebLink
6. Five lithologic units were formulated for Mine Areas 2 and 3. <br /> These include Unit 1 - Sandstone and shale overburden; Unit 2 - <br /> Upper Dakota coal seam and encapsulating very dark gray, <br /> carbonaceous shale; Unit 3 - Interburden sandstone; Unit 4 - Lower <br /> interburden shale; and Unit 5 - Underburden. <br /> 7. Acidic and moderately saline overburden and interburden are the <br /> primary concerns in Mine Areas 2 and 3. Secondary concerns include <br /> the occasional , excessive levels of iron and saturation percentage <br /> and the deficient levels of nitrogen and phosphorous. <br /> 8. Lithologic Units 2 and 4 are unsuitable due to low pH and ABP and <br /> will not be replaced in the upper 3 feet of regraded spoil . <br /> 9. Lithologic Units 1 and 3 are the most desirable suitable <br /> topdressing materials. <br /> 6-54 Revised 04/11/88 <br />